Not everything is boatyball. The mooring fields that have boatyball still have FCFS balls (which may or may not be managed by boatyball). Some mooring fields still have no boatyball at all, so they're entirely FCFS. Depending on the time of year you go and how early you're getting to the mooring field, it should be possible to do FCFS everywhere (though some may still be paid through boatyball, but when you get there, not at 7am).